THÖRESS SE-845 Mono Power Amplifier (Pair)

The THÖRESS SE-845 Mono Power Amplifier represents the absolute pinnacle of Reinhard Thöress’s all-tube amplifier range. Designed to unlock the full potential of the legendary 845 filamentary power triode, these monoblocks operate in pure Single-Ended Class-A mode to deliver 20 Watts of musically potent output. Unlike typical designs that struggle to drive the demanding 845 tube, the SE-845 features a highly sophisticated single-stage driver circuit tailored around EL822 power pentodes. This robust architecture, combined with custom-made in-house C-core output transformers, allows the amplifier to exert iron-fisted control over loudspeakers while retaining the richly textured, holographic, and flowing presentation that only the finest single-ended triodes can achieve.

Key Features:

• Pure Single-Ended Class-A: Delivers 20 Watts of unadulterated Class-A power using the famous 845 filamentary triode for ultimate linearity and tone.
• Advanced Driver Stage: Utilizes a powerful single-stage driver tailored around two EL822 (CV2382) power tubes operated in triode mode to fully excite the 845 grid.
• In-House C-Core Transformers: Features proprietary tape-wound cut core (C-core) output transformers with dual-coil windings, manufactured in-house for vanishingly low distortion.
• Zero Global Feedback: Employs a minimalist circuit topology with absolutely no global feedback, preserving the natural phase integrity and dynamics of the signal.
• DC Heated 845: The 845 tube is DC heated with a cathode balance adjustment to eliminate residual hum and heater voltage ripple for a pitch-black background.
• Point-to-Point Wiring: Built entirely by hand in Germany using meticulous point-to-point wiring techniques for superior reliability and signal purity.

Taming the 845 Giant

The 845 power triode is revered for its sonic capability but is notoriously difficult to drive, requiring a massive voltage swing (approx. 300V peak-to-peak) at the control grid. The SE-845 solves this with a unique single-stage driver circuit using a pair of EL822/CV2382 power tubes running in triode mode at high idle current. This driver stage provides the necessary swing and low output impedance to fully wake up the 845, resulting in a sound that combines the delicacy of a 300B with the scale, authority, and dynamic slam of a high-power amplifier.

The Heart of the System: In-House Transformers

In any Single-Ended amplifier, the output transformer (OPT) is the most critical component. THÖRESS manufactures their OPTs in-house using an exceptionally large tape-wound cut core (C-core). This design offers far superior permeability and linearity compared to standard EI cores. The dual-coil winding technique ensures excellent frequency response and minimal phase shift, allowing the SE-845 to drive 4, 8, and 16-ohm loads with transparency and grip often missing from lesser SET designs.

Silence is Golden

To ensure the music emerges from a silent background, the SE-845 employs specific low-noise design choices. The 845 tube is heated via a filtered DC supply, and a rotary potentiometer allows the user to balance the cathode point perfectly against the filament, nulling out any residual hum. Furthermore, the mains transformer is also produced in-house and mounted on isolation elements to prevent mechanical vibration from reaching the sensitive audio circuit.

Purist Construction

True to the THÖRESS philosophy, the SE-845 eschews balanced circuitry (XLR) in favor of a pure single-ended (RCA) topology, which Thöress believes offers superior sonic fidelity. The chassis is non-magnetic aluminum, powder-coated in the brand’s signature retro-lab aesthetic. Inside, high-grade German-made electrolytic capacitors and a C-core filter choke ensure the power supply is as robust as the signal path is pure.

The Listening Room Difference

We’re a third-generation family business with a brick-and-mortar showroom in Chestertown, Maryland, and a reputation built on trust, not hype. Whether you’re visiting in person or ordering online, we bring decades of experience, personalized service, and honest guidance to every interaction. We don’t just ship boxes. We help build systems, answer your questions like real humans, and make sure every detail of your setup is right, from the cables to the final connection. Our passion is helping you get the most out of your gear, with support that lasts well beyond the sale.

Specifications